CN111202920A

CN111202920A - Protective head cover

Info

Publication number: CN111202920A
Application number: CN202010109491.9A
Authority: CN
Inventors: 荣轩平; 荣国华
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-02-18
Filing date: 2020-02-22
Publication date: 2020-05-29
Also published as: CN211935225U

Abstract

The protective hood comprises a hood, a hood apron, an air supply box, an air supply pipe, an exhaust box and an exhaust pipe, and is characterized in that the upper part of the hood is a closed body and has the shape of a sleeved head, the front part of the hood is a transparent body which does not shield the sight, and the lower part of the hood is provided with an opening and is hermetically connected with the upper part of the hood apron; the lower part of the hood apron is lapped on the body below the neck of the human body, and sealing measures are taken; the front lower part of the hood is provided with an air supply port which is communicated with an air supply box through an air supply pipe, and the air supply box comprises a filter and an air supply machine; the rear part of the hood is provided with an exhaust port which is communicated with an exhaust box through an exhaust pipe, and the exhaust box comprises a filter and an exhaust fan; the air quantity of the blower is larger than the air suction quantity of a human body, and the air quantity of the exhaust fan is larger than or equal to the air quantity of the blower.

Description

Protective head cover

Technical Field

The invention belongs to the field of sanitary protection, and particularly relates to a protective head cover for filtering and isolating viruses, germs, dust and aerosol.

Background

The existing positive pressure protective hood patent provides filtered clean air for health personnel, and is prevented from being invaded by virus, germ, dust and aerosol, and exhaust gas exhaled by the health personnel is not provided with the virus and the germ and is directly discharged into the air without being filtered. However, for suspected and confirmed patients, the exhaust gas exhaled by the suspected and confirmed patients carries viruses and germs, if the suspected and confirmed patients are not filtered, the viruses can be diffused and infected by directly exhausting the exhaust gas into the air, and the traditional positive pressure protective hood has no function of filtering the exhaust gas.

Disclosure of Invention

The invention aims to provide a protective hood which can filter air supply and waste gas, can prevent virus from being infected through air diffusion, and is suitable for healthy people, suspected patients and confirmed patients.

The solution of the invention is: the protective hood comprises a hood, a hood apron, an air supply box, an air supply pipe, an exhaust box and an exhaust pipe, and is characterized in that the upper part of the hood is a closed body and has the shape of a sleeved head, the front part of the hood is a transparent body which does not shield the sight, and the lower part of the hood is provided with an opening and is hermetically connected with the upper part of the hood apron; the lower part of the hood apron is lapped on the body below the neck of the human body, and sealing measures are taken; the front lower part of the hood is provided with an air supply port which is communicated with an air supply box through an air supply pipe, the air supply box comprises an air inlet, a filter, a blower, an air outlet, a controller and a power supply, and the air outlet is connected with the air supply pipe; the rear part of the hood is provided with an exhaust port which is communicated with an exhaust box through an exhaust pipe, the exhaust box comprises an air inlet, a filter, an exhaust fan, an air outlet, a controller and a power supply, and the air inlet is connected with the exhaust pipe; the air volume of the blower is larger than the air intake of the human body, and the air volume of the exhaust fan is larger than or equal to the air volume of the blower.

The working principle is as follows: the protective hood is sleeved on the head of a suspected or diagnosed patient, the hood skirt is lapped on a human body, the hood skirt is adhered with coat clothes by a sealant tape to form sealing, or the hood skirt is tucked in the coat clothes to form sealing. The air feeder in the air feeding box and the exhaust fan in the exhaust box are opened, the outside air passes through the filter, the virus, the germ, the dust and the aerosol are filtered to reach the clean standard, and the outside air enters the hood through the air feeder, the air feeding pipe and the air feeding port of the hood for the breathing of people. The exhaust gas exhaled by the person enters the exhaust box through the exhaust port of the hood and the exhaust pipe, viruses and germs carried in the exhaust gas are filtered by the filter to become clean air, and the clean air is exhausted into the air by the exhaust fan, so that the diffusion and infection of the viruses and the germs to the outside are avoided. Because the air volume of the exhaust fan is larger than that of the blower, negative pressure is formed in the hood, and viruses and germs can be effectively prevented from diffusing out of the hood. When a healthy person wears the protective hood, for example, a doctor does not need to use an exhaust box, only needs to use an air supply box to filter viruses and germs in the air for breathing, and the exhaled waste gas is directly discharged into the air.

Drawings

FIG. 1 is a front protective hood construction

FIG. 2 is a side shield hood configuration FIG. 1

FIG. 3 is a view showing the structure of an air feed box

FIG. 4 is a view showing the construction of an exhaust box

FIG. 5 is a view showing a backflow prevention device structure of FIG. 1

FIG. 6 is a view showing a backflow prevention device structure of FIG. 2

FIG. 7 is a view showing the construction of a filter cassette

FIG. 8 is a side shield hood configuration FIG. 2

FIG. 9 is a side shield hood configuration FIG. 3

FIG. 10 is a side shield hood configuration FIG. 4

FIG. 11 is a side shield hood configuration FIG. 5

FIG. 12 is a side shield hood configuration FIG. 6

FIG. 13 is a side shield hood configuration FIG. 7

FIG. 14 is a side shield hood configuration FIG. 8

Description of reference numerals:

1. hood, 2, hood skirt, 3, sealing tape, 4, plenum box, 5, plenum pipe, 6, plenum port, 7, overhead support, 8, exhaust port, 9, exhaust pipe, 10, exhaust box, 11, plenum box housing, 12, 30, air outlet, 13, plenum box cover, 14, 28, 41, grill, 15, 25, 27, air inlet, 16, 29, 42, filter, 17, 24, fan inlet, 18, 23, fan impeller, 19, 33, controller, 20, 32, fan motor, 21, 31, power supply, 22, exhaust box housing, 26, exhaust box cover, 34, ball slot, 35, floating ball, 36, pull wire, 37, buffer tube, 38, filter housing, 39, filter cover, 40, filter outlet, 43, filter box, 44, face window, 45, choke cover, 46, supply air ring, 47, lower supply air hole, 48, 47, air supply air outlet, 7, overhead support, 8, 9, exhaust air outlet, 10, exhaust box, 11, filter housing, 20, 32, fan motor, 21, 31, power supply air outlet, 22, a meal hole.

Detailed Description

In fig. 1, the upper part of the head cover 1 is a closed body with the shape of a head-covering, and the head cover is made of hard or soft materials, and is air-tight and water-tight, such as: plastic, organic glass and acrylic. The front part of the hood 1 is a transparent body which does not obstruct the view, and other parts can be transparent bodies or opaque bodies. The lower part of the hood 1 is opened and is hermetically connected with the upper part of the hood apron 2, the lower part of the hood apron 2 is overlapped on a human body below the neck of the human body, and a sealing measure is taken, the skirt edge of the hood apron 2 is adhered to coat clothes by using a sealing adhesive tape 3 in the drawing, a circle of the skirt edge is adhered from the forebreast to the back by winding the shoulder to form sealing, or the hood apron 2 is tucked in the coat clothes, or the hood apron 2 is tied at the neck by using a rope and can also form sealing, the hood apron 2 is made of an airtight and waterproof soft material, for example, a transparent plastic film, the hood 1 and the hood apron 2 are made into a whole, the cost is very low, and the disposable product can be made. The front lower part of the hood 1 is provided with an air supply opening 6 which is communicated with an air supply box 4 through an air supply pipe 5, the air supply pipe 5 is preferably made of a plastic hose, the air supply box 4 strides over the chest and can be carried by hand or hung on a waistband, the air supply pipe 5 can be hidden in a jacket and is led to the hood 1 from the lower part of the jacket, and therefore the hood is suitable for preheating outdoor cold air through a human body and then feeding the air to the head in winter without blowing cold air.

In fig. 2, the rear upper part of the hood 1 is provided with an exhaust port 8 which is communicated with an exhaust box 10 through an exhaust pipe 9, the air supply pipe 9 is preferably made of a plastic hose, the exhaust box 10 is back-carried on the back, and the head of a person is provided with a head support 7 which can prevent the hood 1 from shaking and avoid the face from contacting with the hood 1, and the same effect can be achieved as long as a hat with a brim is worn.

In fig. 3, the air box 4 includes an air box case 11, an air box cover 13, an air inlet 15, a filter 16, a blower, an air outlet 12, a controller 19, and a power supply 21, and the air outlet 12 is connected to the air supply pipe 5. The blower comprises a blower air inlet 17, a blower impeller 18 and a blower motor 20, the blower air outlet is connected with the air outlet 12, the blower air inlet 17 is connected with the air outlet of the filter 16, the blower is a centrifugal blower in the figure, and an axial flow blower can also be adopted. The filter 16 may be of different filter materials, the filtering performance and specifications must meet the criteria of N95 or KN95, and the filter 16 is sandwiched between two grids 14 and can be replaced after failure. The air box cover 13 is movable, and has an air inlet 15, and has a grill 14 at the mouth, another grill 14 is fixed in the housing of the air box housing 11, when the air box cover 13 is clamped on the air box housing 11, the filter 16 is clamped between the two grills 14, so that the filter 16 is positioned between the air inlet 27 and the blower inlet 17. The controller 19 can control the start and stop or variable speed operation of the blower, and can display the electric quantity and give an early warning. The power supply 21 is a battery or a rechargeable power supply. The air supply box 4 should be sealed so as not to leak air or water.

In fig. 4, the exhaust box 10 includes an exhaust box housing 22, an exhaust box cover 26, an air inlet 25, a filter 29, an exhaust fan, an air outlet 30, a controller 33, and a power supply 31, and the air inlet 25 is connected to the exhaust duct 9. The exhaust fan comprises a fan air inlet 24, a fan impeller 23 and a fan motor 32, the exhaust fan air outlet is connected with an air outlet 30, the fan air inlet 24 is connected with an air outlet of the filter 29, the exhaust fan is a centrifugal fan in the figure, and an axial flow fan can also be adopted. The filter 29 can be made of different filtering materials, the filtering performance and index must reach the standard above N95 or KN95, and the filter 29 is clamped between the two grids 28 and can be replaced after failure. The exhaust box cover 26 is movable and has two

air inlets

25, 27 which are communicated with each other through the exhaust box cover 26, the air inlet 25 is connected with the exhaust pipe 9, the opening of the air inlet 27 is provided with a grille 28, the other grille 28 is fixed in the shell of the exhaust box shell 22, when the exhaust box cover 26 is clamped on the exhaust box shell 22, the filter 29 is clamped between the two grills 28, and the filter 29 is positioned between the air inlet 27 and the fan inlet 24. The controller 33 can control the start and stop or variable speed operation of the exhaust fan, can display the electric quantity and give an early warning, the power supply 31 adopts a battery or a rechargeable power supply, and the controller 33 and the power supply 31 of the exhaust box 10 can be combined with the controller 19 and the power supply 21 of the air feed box 4 into a controller and a power supply. The exhaust box 10 should be sealed so as not to leak air or water.

Generally, the inspiration volume of a person is 500 milliliters each time, the inspiration time is more than 2 seconds, the required air supply volume is 0.25 liter/second, and the air supply volume of the air feeder is more than 0.25 liter/second of the inspiration volume of the person, so that the breathing requirement of the person can be met. If a suspected or confirmed patient uses the protective hood, negative pressure is applied to the hood to prevent the air exhaled by the patient from diffusing to the outside without being filtered. When the patient exhales, the exhalation volume is 0.25L/s, the air supply volume of the blower is 0.25L/s, the negative pressure in the hood is kept, and the exhaust volume of the exhaust fan is equal to or more than the sum of the two, namely 0.50L/s; when a patient inhales, the inspiratory capacity is 0.25 liter/second, the air supply capacity of the air feeder is 0.25 liter/second, the negative pressure in the hood is required to be kept, the exhaust capacity of the exhaust fan is required to be more than zero, but the air feeder and the exhaust fan are not easy to regulate the speed and are operated continuously at a constant speed, the air supply capacity of the air feeder is required to be more than the inspiratory capacity of the human, the air volume of the exhaust fan is required to be more than or equal to the air volume of the air feeder, the air volumes of the air feeder and the exhaust fan can be determined according to the pressure value requirement in the hood 1, the material of the hood 1 is preferably selected from hard materials, and.

The using method is that the head cover 1 is sleeved on the head of a suspected or diagnosed patient, the head cover apron 2 is lapped on the human body, the head cover apron 2 is adhered with coat clothes by the sealing adhesive tape 3 to form sealing, or the head cover apron 2 is tucked in the coat clothes to form sealing. The blower in the air supply box 4 and the exhaust fan in the exhaust box 10 are opened, the outside air passes through the filter 16, the virus, the germ and the dust are filtered to reach the clean standard, and the outside air enters the hood 1 through the blower, the air supply pipe 5 and the hood air supply opening 6 for the breathing of people. The exhaust gas from the person is exhausted into the exhaust box 10 through the exhaust port 8 of the hood and the exhaust pipe 9, the virus and germ carried in the exhaust gas are filtered by the filter 29 to become clean air, and the clean air is exhausted into the air by the exhaust fan, thereby avoiding the diffusion and infection of the virus and germ to the outside. When a healthy person uses the protective hood, such as a doctor, the doctor does not need to use the exhaust box 10, only needs the air supply box 4 to filter viruses and germs in the air for breathing, the exhaled waste gas is directly discharged into the air, and the air supply quantity is larger than the air suction quantity of a human body because only the air supply box 4 supplies air to the protective hood, so that the protective hood is always in a positive pressure state, the viruses and germs outside can be prevented from diffusing into the hood, and an effective protective effect is achieved.

In fig. 5, when the exhaust box 10 is not used by a healthy person, in order to prevent the occurrence of a large negative pressure in the hood 1 accidentally, the polluted air with virus outside flows back into the hood 1 from the exhaust port 8, the exhaust port 8 is provided with a backflow prevention device, which comprises a spherical notch 34, a floating ball 35, a pull wire 36 and a buffer tube 37, wherein the spherical notch 34 is positioned in the exhaust pipe 9, the waste gas flows through the exhaust pipe, the curved surface shape of the mouth part of the spherical notch is matched with the outer surface of the floating ball 35, the floating ball 35 is made of a light material and is fixed on the pipe wall by the pull wire 36, the floating ball 35 can move rapidly under the push of the air, the buffer tube has a smooth surface and is tightly matched with the spherical notch 34, the waste gas in the figure is discharged into the air through the spherical notch 34, the floating ball 35 and the.

In fig. 6, the floating ball 35 is located between the spherical notch 34 and the buffer tube 37, when the air backflow occurs, the external contaminated air with virus enters the buffer tube 37, the waste gas in the buffer tube 37 is pushed to flow back, so that the waste gas pushes the floating ball 35 to be clamped at the spherical notch 34, and because the two are matched in shape and smooth in surface, a closed state is formed, and the external contaminated air with virus is blocked outside the head cover 1. The length of the buffer tube 37 is such that sufficient exhaust gas can push the floating ball 35 to be clamped in the spherical notch 34, and the outside polluted air with virus can be prevented from passing through the floating ball 35, passing through the spherical notch 34 and entering the head cover 1.

In fig. 7, a filter cassette is mounted in the vent 8 and includes a filter cassette housing 38, a filter cassette cover 39, a filter cassette outlet 40, a grill 41, and a filter 42, the filter cassette cover 39 being removable and having the filter cassette outlet 40 and a grill 41 at the mouth, the other grill 41 being secured within the housing of the filter cassette housing 38 to sandwich the filter 42 between the grills 14 when the filter cassette cover 39 is snapped onto the filter cassette housing 38. Thus, the exhaust gas in the hood 1 enters the filter box through the exhaust port 8 and the exhaust pipe 9, and viruses and germs are filtered and then discharged to the air. When negative pressure is suddenly generated in the head cover 1, the outside air flows back into the head cover 1 through the air outlet 40 of the filter box, the grille 41, the filter 42, the exhaust pipe 9 and the exhaust port 8, but viruses, germs and dust in the air are filtered by the filter 42, so that the harm to human bodies is avoided. The filter 42 may be made of high-efficiency filtering material, or may be covered at the mouth of the filter box with a common mask.

In fig. 8, the protective hood is suitable for healthy people, positive pressure is provided in the hood 1, and the exhaust pipe 9 is provided with the filter box 43, so that viruses, germs and dust caused by air backflow can be effectively filtered.

In fig. 9, the protective hood is suitable for suspected or confirmed patients, the exhaust pipe 9 is provided with a filter box 43, the cover 13 of the air feeding box 4 is provided with two covers with different structural forms, one cover is the same with the cover 26 of the air discharging box 10 in structural form, the air inlet 25 of the air feeding box is communicated with the air feeding pipe 5, the air feeder is converted into an exhaust blower, under the suction of the air feeder, viruses, germs and dust in the air are filtered by the filter box 43 to become clean air, the clean air enters the hood 1 through the exhaust pipe 9 and the air outlet 8 for the patients to breathe, the waste air with the viruses and the germs enters the air feeding box 4 through the air inlet 6 and the air feeding pipe 5, the viruses and the germs are filtered by the filter 16 to become clean air, and then the clean air is discharged into the air through the air feeder and the air outlet 12, meanwhile, the interior of the protective hood is under negative pressure, so that, The germs diffuse into the air. The protective hood omits an exhaust box 10, has simple structure, low cost and good protective effect, and can be used by healthy people and suspected or confirmed patients as long as two gas delivery box covers 13 are provided.

In fig. 10, when hot and humid air exhaled by a human body meets cold air from the outside on the face window 44 of the hood 1, fog and dew are easy to form, and the sight of the human body is affected, therefore, the face window 44 is made of double layers of transparent hard materials, the two layers are in vacuum, and the face window 44 is insulated from the inside and the outside to prevent cold from the outside from being transmitted into the face window 44; or the face window 44 is made of a single-layer material, and antifogging paint is coated inside the face window; or the face window 44 is made of transparent and breathable gauze material, and the waste gas is directly discharged from the face window 44 instead of the air supply opening 6 and the air exhaust opening 8, so that the air supply box 4 is required to have enough air quantity to keep the interior of the hood 1 always at positive pressure, and the external viruses, germs and dust are prevented from flowing backwards into the hood 1. In order to prevent hot and humid air exhaled by a human body from flowing to the face window 44, the lower part of the face window 44 is fixedly connected with an air blocking cover 45, one side of the air blocking cover is hermetically connected with the inner surface of the hood 1, the other side of the air blocking cover is hermetically clamped above the nose bridge, the face and below the eyes of the human body, the air blocking cover 45 can also be separately connected with the hood 1, hung on the face of the human body through a pull rope and communicated with the air supply opening 6, and therefore the air blocking cover 45 guides the exhaust gas exhaled by the human body to the air supply opening 6 or the air exhaust opening 8 in an organized manner so as to prevent.

In fig. 11, the head support 7 has an air supply loop 46 surrounding the head and located at the forehead, the air supply loop 46 has a plurality of lower air supply holes 47 at the forehead position, and the other end of the air supply loop 46 is connected with an external air supply pipe, such as the air supply box 4 and the air exhaust box 10, and the air is supplied by the air exhaust box 10, so that the external air is filtered by the air exhaust box 10 and then sent to the air supply loop 46 through a hose, and is supplied downwards at the lower air supply holes 47, and is exhausted by the air supply box 4 at the lower part of the hood 1, and the hot and humid air exhaled by the human body is exhausted therewith, thereby preventing the hot and humid air exhaled by the human body from floating upwards along the face window and the face, and preventing fog and dew formation in the face window, and the air in the hood 1 is at positive pressure because the air supply amount of the air exhaust box 10 is.

In fig. 12, only the blowing box 4 is used for exhausting air, and under the suction action of the blowing box 4, the outside air is filtered and then enters the hood 1 through the blowing ring 46 and the lower blowing holes 47, and at this time, the inside of the hood 1 is under negative pressure.

In figure 13, the air supply box 4 supplies air, the air supply hose enters the protective hood below the hood apron 2 and is communicated with an air supply ring pipe 46 at the back of the head, the method cannot see the pipe and is more attractive, and the interior of the hood 1 is in positive pressure at the moment. The air supply hose and the hood skirt 2 should be sealed, and the air supply hose can also pass through the neckline from the inside of the coat and is communicated with an air supply ring pipe 46 at the back of the head.

In fig. 14, a meal hole 48 is formed at the mouth position of the human body on the face window of the hood 1 for feeding meal into the mouth, the meal hole 48 may be provided in cooperation with the air feed port 6, and the meal hole 48 may be formed directly on the plastic film for the disposable hood 1 made of the plastic film. Since the dining hole 48 is larger than the air inlet 6, the air leakage amount is large, and the air supply box 4 is required to have a large air supply amount in order to maintain the hood 1 at a positive pressure during a meal.

If an oxygen cylinder or other oxygen supply device is used instead of the air supply box 4, air can be supplied into the hood 1 and positive pressure can be maintained. The protective hood of the present invention, if combined with a sports helmet, will serve two purposes.

The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. Any simple modification, equivalent change and modification of the above embodiments according to the technical spirit of the present invention fall within the scope of the present invention.

Claims

1. The protective hood comprises a hood, a hood skirt, an air supply box, an air supply pipe and an exhaust pipe, and is characterized in that the upper part of the hood is a closed body and has the shape of a sleeved head, the front part of the hood is a transparent body which does not shield the sight, the lower part of the hood is provided with an opening and is hermetically connected with the upper part of the hood skirt, the lower part of the hood skirt is overlapped on the body below the neck of the human body, and a sealing measure is taken; an air supply opening is arranged at the front lower part of the hood and communicated with an air supply box through an air supply pipe; the air supply box comprises an air supply box shell, an air supply box cover, an air inlet, a filter, an air feeder, an air outlet, a controller and a power supply, wherein the air outlet is connected with an air supply pipe; the cover of the air feeding box is movable and is provided with an air inlet, a grid is arranged at the mouth part, the other grid is fixed in the shell of the air feeding box, the cover of the air feeding box is clamped on the shell of the air feeding box, the filter is clamped between the two grids, and the filter is positioned between the air inlet and the air inlet of the fan; the rear part of the head cover is provided with an exhaust port which is communicated with the exhaust pipe.

2. The protective hood according to claim 1, wherein one end of the exhaust pipe is communicated with the exhaust port of the hood, and the other end is communicated with an exhaust box, the exhaust box comprises an exhaust box shell, an exhaust box cover, two air inlets, a filter, an exhaust fan, an air outlet, a controller and a power supply, the exhaust fan comprises a fan air inlet, a fan impeller and a fan motor, the exhaust fan air outlet is connected with the air outlet, the fan air inlet is connected with the air outlet of the filter, the air volume of the exhaust fan is larger than or equal to the air volume of the blower, and the exhaust fan is a centrifugal fan or an axial flow fan; the exhaust box cover is movable and provided with two air inlets which are communicated with each other through the exhaust box cover shell, one air inlet is connected with the exhaust pipe, the opening part of the other air inlet is provided with a grating, the other grating is fixed in the shell of the exhaust box shell, the exhaust box cover is clamped on the exhaust box shell, the filter is clamped between the two gratings, and the filter is positioned between the air inlet and the air inlet of the fan.

3. The protective hood according to claim 1 wherein the anti-drainback means is located at the exhaust port of the hood and comprises a ball-shaped slot, a floating ball, a pull wire, and a buffer tube, wherein the ball-shaped slot is located in the exhaust tube and through which exhaust gas flows, the curved surface of the mouth of the ball-shaped slot matches the outer surface of the floating ball, the floating ball is made of light material and has a smooth surface, the floating ball is fixed to the wall of the tube by the pull wire, and the floating ball moves rapidly under the push of air and matches the ball-shaped slot closely, and the floating ball is located between the ball-shaped slot and the.

4. The protective hood according to claim 1 wherein a filter cartridge is mounted to the hood exhaust duct and includes a filter cartridge housing, a filter cartridge cover, a filter cartridge outlet, a grill, and a filter, the filter cartridge cover being removable and having the filter cartridge outlet and the grill at the mouth, the other grill being secured within the housing of the filter cartridge housing, the filter cartridge cover being secured to the filter cartridge housing to sandwich the filter between the grills, the exhaust or ambient air within the hood being filtered by the filter.

5. The protective hood according to claim 1, wherein the air box has two air box covers with different structural forms, one of the air box covers has the same structural form as the air box cover of the air box, an air inlet of the air box cover is communicated with the air supply pipe, the air supply machine is converted into an exhaust fan, under the suction of the air supply machine, viruses, germs and dust in the air are filtered by the filter box to become clean air, the clean air enters the hood through the exhaust pipe and the exhaust port to be breathed by a patient, the clean air is changed into waste air with viruses and germs, and then the waste air enters the air supply box through the air supply port and the air supply pipe, the viruses and germs in the air are filtered by the filter to become clean air, and then the clean air is exhausted into the air through the air supply machine and the air outlet, the protective hood has negative pressure, and.

6. The protective hood according to claim 1 having an anti-fog face window formed of two layers of transparent hard material, vacuum between the two layers, and heat insulation between the inside and outside; or a single-layer material is adopted, and antifogging paint is coated inside the single-layer material; or the transparent and breathable gauze material is adopted, and the exhaust gas exhaled by the human body is directly exhausted from the face window.

7. The protective hood of claim 1 wherein the protective hood has an air blocking cover below the face window, which is fixedly or separately attached to the hood and is sealingly engaged over the nose bridge, face and under the eyes of the person to organically divert exhaust exhaled by the person to the air delivery or exhaust port to prevent flow to the face window.

8. The protective hood according to claim 1 wherein the head support frame in the protective hood has a supply air loop surrounding the head at a height above the forehead position, the supply air loop having a plurality of lower supply air holes in the forehead position and an external supply air duct connected to the other end of the supply air loop.

9. The protective hood of claim 1 wherein a dining hole is provided in the face of the hood at the mouth of the person.